The present invention relates to methods and apparatus for the diagnosis and other analyses of operations of a semiautomatic machine such as a copy production machine of the transfer electrographic type.
A major factor is cost of semiautomatic machines is the maintenance cost. Any procedures and facilities which tend to reduce maintenance time have a salutory effect on cost reduction of machine operation. Many semiautomatic machines having heavy operator involvement in the operation have a multitude of interacting parts and control circuits. Error conditions can be detected by diverse symptoms wherein one symptom can indicate any one of a large plurality of error conditions. In diagnosing such machines for error conditions, including improving adjustment of the various parts of the machine, the history of the machine can be used to advantage. However, the history of the machine, including the error conditions, must be so organized and readily available to facilitate reduced maintenance time.
Semiautomatic machines such as convenience copiers will have attachable features which, if attachable in the field, can reduce total product cost. Such attachable features for convenience copiers are collators, document feeds and the like.
In later model convenience copiers, programmed digital computers have replaced relay control circuits and solid state logic or switching circuits for controlling such machines. Such use of programmed digital computers enables many more functions to be performed, thereby complicating the diagnostics and analyses of machine failures. Generally, such programmed computers operate in accordance with a program of instruction words in a read only store (ROS). Such programs of instruction words relate specifically to one or more portions of the machine being controlled. If a feature is to be added, i.e., a collator is to be added, then such ROS should contain programs applicable to such added collator. If the maintenance personnel were to add or to remove such ROS portions each time a feature is changed, installation time would be increased while the possibility of introducing errors into the machine programming would be high. Accordingly, it is desired to install initially all code that could be used with the machine at the time of manufacture. This statement is true for all features whether or not the features are actually shipped with the machine. After the machine is in its operating site and the feature is to be added, the additional code then can be invoked for controlling that additional feature. Means must be provided for inhibiting operation of the code when the feature is not activated but permitting it when it is.